The present invention relates generally to the field of ink containers, and more particularly, to broken bag sensing for metallized film ink bag designs.
Prior art broken bag detection designs for metallized film ink bags typically have pads routed to the interior of the ink bottle containing the metallized bag, but external to the bag itself. Such pads are intended to short when exposed to conductive ink. The pads in these prior art ink bag detection designs were small and integrated into a flex circuit. However, such broken bag sensor designs typically would only work properly for large leaks. To operate properly, the contact pads in such prior art designs must be exposed to the ink that has leaked. Accordingly, the pads must be positioned in the vicinity of the leak location in order to be effective. In the event of a small leak, or if the supply orientation is disadvantageous, then the break in the bag will not be detected. Non-detected broken bags lead to printer and possibly customer property damage by contaminating the air system with ink. Such leaks could also potentially overflow beyond the capacity of the ink trap in the air system.
The present invention comprises in one embodiment an ink system including a broken bag sensing circuit for use with a conductive ink, comprising: an ink containment bag with a metallized layer insulated from a bag interior; a first electrical contact with the metallized layer; a second electrical contact communicating with conductive ink contained within the ink containment bag; an electrical connection between the first and second electrical contacts; and a measurement device for measuring an electrical characteristic between the first and second contacts.
In a further embodiment of the present invention, a printer with a broken bag sensing circuit for use with conductive ink is provided, comprising: an ink containment bag with a metallized layer insulated from a bag interior; a first electrical contact with the metallized layer; a second electrical contact communicating with conductive ink contained within the ink containment bag; an electrical connection between the first and second electrical contacts; and a measurement device for measuring an electrical characteristic between the first and second contacts.
In a further embodiment of the present invention, a method is provided for sensing a broken ink bag, comprising: sensing an electrical characteristic of a circuit including a metallized layer in a containment bag which layer is insulated from an interior of the bag and conductive ink in the interior of the containment bag; and generating a signal if the electrical characteristic equals or passes a predetermined threshold value.